ENIAC

Electronic Numerical Integrator and Computer
ENIAC

   <computer> (ENIAC) The first electronic {digital computer} and
   an ancestor of most computers in use today.  ENIAC was
   developed by Dr. {John Mauchly} and {J. Presper Eckert} during
   World War II at the Moore School of the {University of
   Pennsylvania}.

   In 1940 Dr. {John Vincent Atanasoff} attended a lecture by
   Mauchly and subsequently agreed to show him his binary
   calculator, the {Atanasoff-Berry Computer} (ABC), which was
   partially built between 1937-1942.  Mauchly used ideas from
   the ABC in the design of ENIAC, which was started in June 1943
   and released publicly in 1946.

   ENIAC was not the first digital computer, {Konrad Zuse}'s {Z3}
   was released in 1941.  Though, like the ABC, the Z3 was
   {electromechanical} rather than electronic, it was freely
   programmable via paper tape whereas ENIAC was only
   programmable by manual rewiring or switches.  Z3 used binary
   representation like modern computers whereas ENIAC used
   decimal like mechanical calculators.

   ENIAC was underwritten and its development overseen by
   Lieutenant Herman Goldstine of the U.S. Army Ballistic
   Research Laboratory (BRL).  While the prime motivation for
   constructing the machine was to automate the wartime
   production of firing and bombing tables, the very first
   program run on ENIAC was a highly classified computation
   for Los Alamos.  Later applications included weather
   prediction, cosmic ray studies, wind tunnel design,
   petroleum exploration, and optics.

   ENIAC had 20 {registers} made entirely from {vacuum tubes}.
   It had no other no memory as we currently understand it.  The
   machine performed an addition in 200 {microseconds}, a
   multiplication in about three {milliseconds}, and a division
   in about 30 milliseconds.

   {John von Neumann}, a world-renowned mathematician serving on
   the BRL Scientific Advisory Committee, soon joined the
   developers of ENIAC and made some critical contributions.
   While Mauchly, Eckert and the Penn team continued on the
   technological problems, he, Goldstine, and others took up the
   logical problems.

   In 1947, while working on the design for the successor
   machine, EDVAC, von Neumann realized that ENIAC's lack of a
   central control unit could be overcome to obtain a rudimentary
   stored program computer (see the Clippinger reference below).
   Modifications were undertaken that eventually led to an
   {instruction set} of 92 "orders".  {Von Neumann} also proposed
   the {fetch-execute cycle}.

   [R. F. Clippinger, "A Logical Coding System Applied to the
   ENIAC", Ballistic Research Laboratory Report No. 673, Aberdeen
   Proving Ground, MD, September 1948.
   (http://ftp.arl.mil/~mike/comphist/48eniac-coding)].

   [H. H. Goldstine, "The Computer from Pascal to von Neumann",
   Princeton University Press, 1972].

   [K. Kempf, "Electronic Computers within the Ordnance Corps",
   Aberdeen Proving Ground, MD, 1961.
   (http://ftp.arl.mil/~mike/comphist/61ordnance)].

   [M. H. Weik, "The ENIAC Story", J. American Ordnance Assoc.,
   1961. (http://ftp.arl.mil/~mike/comphist/eniac-story.html)].

   [How "general purpose" was ENIAC, compared to Zuse's {Z3}?]

   (2003-10-01)
    

ENIAC
       Electronic Numerical Integrator And Computer